The fuels saving modes of the '769 Patent involve a step forward in the evolution of “skipping” technology. For the first time, the piston of the skipped piston and cylinder assembly actually enters into the creation of power rather than simply being neutral or requiring power from the rest of the engine to be moved through repeated cycles without cycle events taking place. The skipped piston enters into the creation of power because it shares combustion chambers of two paired assemblies. By means of a passage between the combustion chambers, the increased pressure conditions in the cylinder of its paired assembly resulting from the internally fired power drive stroke therein causes the associate pistons of the cylinder to undergo a simultaneous shared power drive stroke. Since the skipped piston is directly connected to the crankshaft, its shared power drive stroke creates power in the engine. A feature of the '769 patent is that the fuel injectors of the paired assemblies are computer controlled so to select whether only one of the two injectors is skipped in which case the shared power stroke takes place or (2) neither injector is skipped in which normal operation takes place. For convenience of language, these selectable modes of operation can be identified as (1) a single fire double expansion and (2) a double fire single expansion respectively.